Delimber

ABSTRACT

A machine for removing the limbs from a tree while the same is being propelled through said machine, comprising in combination a frame including an aperture therein through which the tree passes during processing, a plurality of arcuate cutting members each having cutting edges facing in a substantially common direction, secured to said frame in substantially symmetrical arrangement about said aperture and adjacent the periphery of said aperture, each of said cutting members being pivotally secured to said frame by at least one link member and at least one arm member, and power means secured to said arm members and said frame for moving said arm members relative to said frame thereby providing traverse movement of said cutting members relative to said aperture.

United States Patent [1 1 Palfy Nov. 6, 1973 [54] DELIMBER 3,596,6908/1971 Hamilton t. 144/2 2 [75] Inven or Robe M k os Pa y La al es3,653,417 4/1972 Cervenak 144/2 Z Rapides, Quebec, Canada I PrimaryExaminer-Gerald A. Dost [73] Assigneez Logging Development Corporation,5 & ONeil Montreal, Quebec, Canada [22] Filed: Mar. 7, 1972 [57]ABSTRACT Appl. No.: 232,398

Foreign Application Priority Data Mar. 9, 1971 Canada .7 107262 US. Cl.144/2 Z, 144/208 E Int. Cl A0lg 23/00 Field of Search 144/2 Z, 3 D, 208R,

References Cited UNITED STATES PATENTS 10 3/197] McElderry 144/2 Z 525/1965 Larson 144/3 D 74 8/1968 Hahn 144/309 AC 26 8/1969 Larson 144/2 ZA machine for removing the limbs from a tree while the same is beingpropelled through said machine, comprising in combination a frameincluding an aperture therein through which the tree passes .duringprocessing, a plurality of arcuate cutting members each having cuttingedges facing in a substantially common direc tion, secured to said framein substantially symmetrical arrangement about said aperture andadjacent the periphery of said aperture, each of said cutting membersbeing pivotally secured to said frame by at least one link member and atleast one arm member, and power means secured to said arm members andsaid frame for moving said arm members relative to said frame therebyproviding traverse movement of said cutting members relative to saidaperture.

9 Claims, 10 Drawing Figures PATENIEDHm slam SHEET 1 0F 5 PATENTED 5SHEET 2 BF 5 PATENTED NOV 6 I975 SHEET 5 OF 5 DELIMBER This inventionrelates to tree delimbing devices and more particularly to the typeknown generally in the pulpwood harvesting industry as a stripperdelimber.

Examples of known stripper type delimbers are disclosed in the followingpatents: Hamilton et al Canadian Patent No. 860,080 dated Jan. 5, 1971;Hahns Canadian Patent No. 841,380 dated May 12, 1970;

Faller et al Canadian Patent No. 833,312 dated Feb. 3,

I970; Jorgensens Canadian Patent No. 779,081 dated Feb. 27, 1968;Larsons U.S. Pat. No. 3,461,926 dated Aug. 19, I969; Winbla'd et al U.S.Pat. No. 3,348,592 dated Oct. 24, 1967; and Larsons U.S. Pat. No.3,323,563 dated May 28, 1965.

Two major problems associated with the known devices are the quality ofthe delimbing obtained by such devices which is not always satisfactoryand the operating efficiency of such devices.

In regard-to the operating efficiency of such devices, some knownexamples in the prior art disclose limb cutting members which aremounted so as to move relative to one another in various planes ratherthan a common plane. Accordingly, during operation of such devices ithas been found debris clogs betweenthe cutting members and thus foulsthe operation of the device. A further disadvantage with many presentstripper type delimbers is that the cutting members encircle the tree tobe delimbed and make only point contact with the tree trunk peripheryand leave relatively large sections around the trunk periphery out ofcutter contact which results in a poorly delimbed tree. 1

Accordingly, it is a prime objectof the present inven-- tion to providea device which will perform efficiently and reliably and which willdelimb trees satisfactorily.

It is a further object to provide a device which will operate inconjunction with other tree processing de-v vices, for example, a devicewhich can be mounted in ganged relationship with other tree processingdevices of the type known generally as the annular ring type. It will beappreciated that such device must operate in conjunction with apredetermined feed path along which the tree travels during processingby the other processing units mounted in conjunction therewith.

It is a further object of the invention to provide a devicewhich willdelimb 'trees efficiently regardless of varying diameters, namely toprovide a delimber whereby the cutting members contact the periphery ofthe tree trunk generally to the same extent when processing'a givendiameter and a relatively larger or relatively smaller diameter. 7 g

It is a still further object of the present invention to provide adevice which includes tree limb cutting 'members which are mountedso asto be movable relative to one another in a common. plane.

In one aspect of, the invention, there .is provided a machine forremoving the limbs from a tree while the present invention;

FIG. 2 is a side elevational view of the delimber shown in FIG. 1;

FIG. 3 is a part sectional elevational view taken along line 33 in FIG.2;

FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. 1;

FIG. 5 is a cross-sectional view taken along line 55 in FIG. 3;

FIG. 6 is a crosssectional view taken along line 66 in FIG. 3; I

FIG. 7 is a cross-sectional view taken along line 77 in FIG. 1;

FIG. 8 is an elevational view of a tree topping device shown secured toa frame.(in phantom line) in accordance with'the present invention;

FIG. 9 is a side elevational view of the tree topping device shown inFIG. 8; and

FIG. 10 is a part sectional view taken along line 10-10 in FIG. 8.

Referring to FIG. 1, shown therein is an annular ringtype stripperdelimber 10, consisting of a frame 20,

having a plurality of arcuate cutting members 30 mounted thereon, eachby an arm member 40 and a The frame 20 is a box-like structureconsisting of a front plate 11 and a rear-plate 12 secured to aperipheral frame 13 as by welding and/or bolt nut assemblies.The'peripheral frame 13 holds the front and rear plates in spacedrelation relative to one another and portions of the front and rearwalls and/or peripheral frame may be detachable providing access ,to anarea within the enclosure provided by the plates and frame.

The peripheral frame 13 is provided with two pairs of lugs- 19, eachhaving an aperture 19A therethrough for receiving a pin to mount theassembly on respective ones of the pair of spaced-apart rigid beammembers. The pairs of lugs l9 are directed outwardly in a direction awayfrom one another as illustrated in FIG. 1, thereby adapting the assemblyto be mounted on a framework, for example, a pair of spaced-apart beamsdisclosed in detail in Hamilton U.S. Pat. No. 3,351,107 issued Nov. 7,1967.

The frame 20 has a central aperture 14 through which the trees passendwise during processing thereof, the aperture being defined by acircular housing 15 having a tapered section 16 connected to a terminalend section 17 of smaller diameter. The axis of the aperture 14 is, infact, a longitudinal axis of a feed path along which a tree passesthrough the delimber while being propelled endwise for processingthereof in removing limbs with the cutters. Various means may be used topropel the trees, for example, driven feed rolls disclosed in theaforementioned U.S. Pat. No. 3,35 l ,107 or as disclosed in CanadianPatent No. 807,454, issued Mar. 4, I969.

The arcuate cutting members 30 include a knife holder 31 and a cuttingblade 32 detachably secured thereto. Each cutting blade has a cuttingedge 32A facing in the direction toward trees fed into the aperture 14from the infeed side and arcuate about the path along which the treetravels during processing thereof.

Each knife holder 31 comprises an elongated block 33 having an arcuateedge 33A to accommodate the arcuate cutting blade 32. Block 33 has apair of spacedapart apertures 33B which accommodate bushings 33C asshown in FIG. 4. If desired, additional plate members 34 as indicated inFIGS. 1, 4 and 7 may be secured by welding or the like in spacedrelation to block 33 utilizing a spacer block 34A. The plate members 34will thus move with the cutting member 30 and provide a selected partialblockage of aperture 14, the blockage increasing as the free end ofcutting blade 32 moves towards the central axis of aperture 14. The saidblockage of the aperture relative to the cutting members is an optionalfeature which under certain conditions may enhance operation of thedelimber by preventing debris to jam in between the terminal ends of thecutting blade 32.

The cutting blade 32 is detachably secured to knife holder 31 by aplurality of countersunk screws 35 thus providing simple servicing inreplacing worn out cutting members.

.As mentioned previously the cutting members 30 are secured to frame 20by an arm member 40 and a link member 50. The mounting of the cuttingmember 30 is best shown in FIG. 4 wherein it will be seen that armmember 40 comprises a sleeve member 41 having a pair of members 42 and43 secured thereto in spaced relation by welding or the like. Members 42and 43 are apertured to receive sleeve 41 and also special cap screw 44.Members 42 and 43 may be made from plate material suitably contoured. Itwill be noted that adjacent bushing 33C and members 42 and 43 there arethrust washers 44A. It will be realized that special cap screw 44 is ashouldered shaft for bearing 33C. Sleeve 41 includes a suitable aperturefor journalling on shaft 71 and is secured under the head 71A thereof. Athrust washer 41A is inserted adjacent sleeve 41 and bosses 73 on shaft71.

Link member 50 includes a pair of members 51 and 52 as referred to inFIG. 4 and which are positioned in spaced relation by a pair of plates53 and 54 welded thereto. Plates 51 and 52 are apertured to receivespecial cap screw 44 and they are suitably contoured being made fromplate material. Link member 50 is secured at one end to block 33 andutilizes thrust washers 44A adjacent members 51 and 52 respectively.Link member 50 is secured to frame 20 in similar fashion to block 33.Members 51 and 52 straddling a lug 51A which in turn is secured tobracket 518 which is secured to plate 11 by welding or the like. Bracket518 comprising a plate-like member 51C secured perpendicular to plate 11and having a gusset 51D which is welded to member 51C and plate 11.

Lubrication fittings are located adjacent bearings of arm member 50 andlink member 50 as indicated in FIG. 1.

The plurality of pivots shown in FIG. 3 are secured to frame 20 as shownin detail in FIG. 4. Pivot 70 comprises a shaft 71 having a hexagonalhead 71A and a threaded portion 71B which accommodates a castellated nut71C locked by cotta pin 71D. A suitable spacer 71E is located under thehead of the castellated nut and abuts against a thrust bearing 71F.Shaft 71 is supported in frame 20 by a pair of bearings 72 suitablysecured in a pair of bosses 73 welded in position in frame 20.

Shaft 71 has keyed to it crank arm 74 in two instances as shown in FIG.3. Crank arms 75 and 76 are of similar construction but slightlydifferent configuration to suit respective connections to power means 30and link means 60.

Crank arms 74, 75 and 76 are keyed in position on shaft 71 by key 71G inconjunction with cap screws 71H. Crank arms 74, 75 and 76 may befabricated from steel plate suitably contoured and apertured to receivesteel tubing and thereafter welded, the tubing being cut to requiredlength.

The linkage system 60 comprises a plurality of link members 61, 62 and63 interconnecting crank arms 74, 75 and 76. Link members 61, 62 and 63may be fabricated from steel bar stock or tubing cut to suitable length,contoured apertured and welded so as to provide clevises 64interconnected by members 65. Clevises 64 are interconnected torespective crank arms 74, 75 and 76 by pins 66 held captive by cotta pin67.

Power means 80 which includes a fluid cylinder 81 connected at thepiston rod end to crank arm 75 via pin 66 held captive by cotta pin 67is pivotally mounted at the cylinder end by a pin 82 as shown in FIGS. 3and 5. The fluid cylinder 81 may be of any suitable commerciallyavailable type. It is, although not shown in the Figures, interconnectedto a hydraulic power source controlled via suitable valving and locatedremote from the delimber. Referring to FIG. 5 which shows the detailedinterconnection of fluid cylinder 81. Pin 82 is mounted in a pair ofbushings 82A which may be made from selected tubing cut to suitablelength and welded into position in frame 20. It will be noted that pin82 is held captive within frame 20 by end plate 8213 secured by capscrews 82C threaded into frame 20. Fluid cylinder 81 at the cylinder endincludes a bushing housing a commercially available spherical bearing82D mounting the same upon pin 82. The piston end of fluid cylinder 81includes a further spherical bearing 8213 for mounting upon pin 66 incrank arm 75. Spacers 82F and 82G are inserted respectively on pins 66and 82 as shown in FIG. 5 to take up end play in respective bearings 82Dand 82E.

It will be noted that crank arm 75 connection to the piston rod end offluid cylinder 81, includes a pair of plate members 75A suitablycontoured and apertured to receive bosses 75C and 75B welded thereto.Also, pin 66 includes a head portion 66A. Crank arm 75 is likewise keyedto pivot 70 in similar fashion to crank arms 74 and 76. It will befurther noted that side plate 13 adjacent the fluid cylinder 81hydraulic port connection is apertured to provide access for hydraulichosing or piping connections to fluid cylinder 81.

With regard to the link connection to crank arm 76 which is typical ofall clevis 64 connections to crank arms 74 and 75, FIG. 6 illustratesthe connection in detail. It will be noted that a bearing 68 is fittedwithin the crank arm 76 so as to minimize wear at the pivot connection.The bearing may be of any commercially available suitable type.

From the foregoing, it will be realized that the pivots 70 to which armmembers 40 are connected, are rotated by a power means which includes alink system interconnecting the pivots 70 and interconnected to a fluidcylinder, the whole of which is conveniently enclosed for protectionwithin the box-like frame 20.

Referring to FIG. 2, additional lugs 19B and 19C are secured to rearplate 12 for use in securing arm members of tree feed rolls, which arenot shown, if desired. Attention is drawn to FIG. 3 wherein four groupsof four nuts 19D which are welded about apertures in plate 12 areutilized for securing a'pair of the lugs 19B and a pair ofthe lugs 19Crespectively with cap screws not shown.

From the foregoing, it will be evident that upon activation of fluidcylinder 81 which causes the piston rod to extend therefrom, pivots 70will rotate in a clockwise direction thereby causing the cutting members30 to move in a direction away from the central axisof aperture l4.Reverse direction of the piston rod of fluid cylinder 81 will naturallyreverse the direction of the movement of cutting members 30 thusbringing them to the central axis of aperture 12 as shown in phantomline in FIG. 1.

The fluid cylinder 81 may, if desired, be connected to a hydrauliccircuit which includes a hydraulic accumulator. Such arrangement willprovide a certain resilience to the mounting of the cutting members thusgiving some flexibility to the clamping action of the cutters whenembracing a tree being or'to be processed.

In operation, a tree to be delimbed is fed by a suitable means such as aboom and grapple to the delimber. Examples of suitable boom and grappleassemblies are disclosed in" Hamilton et al Canadian Patent No. 860,080dated Jan. 5, 1971 and Hamiltons US. Pat. No. 3,351,107 dated Nov. 7,1967 said boom being mountedon a suitable'frame adjacent the delimber10.

The butt end of the tree is introduced through aperture 14, thelongitudinal axis of thetree being generally coincident with thelongitudinal axis passing through aperture l4.vThe tree butt is advancedthrough the aperture 14 by said boom and grapple sufficiently to engagetree propelling'means such as feed rolls or other suitable tree feedingmeans not shown which thus grips the leading butt end of the tree andcommences to pro- The aforementioned iris-like motion of the fourcutting members as shown in FIG. 1, combined with the arcuate shape ofthe cutting edges 32A of cutting blades 32, the path of the cuttingedges 32A of cutting blades 32 as they cross the fact of aperture 14 asprovided by the ratio of dimensions of arm members 40 and link members50 and connections and disposition thereof on frame 20, provides astripper type delimber wherein the cutting edges 32A of the cuttingmembers 30 encircle the trunk of a tree in a common plane and the extentof cutter contact with the trunk is substantially the same over avariety of tree diameters ranging from the smallest as diagrammaticallyshown in FIG. 1 by phantom line, to the largest which is determined bythe diameter of tree which will pass through aperture 14, at circularhousing portion 17 diameter.

Therefore, as the tree to be delimbed is propelled through aperture 14by the means discussed and with the cutting members 30 being biasedagainst and encircling the tree trunk as discussed, the tree isefficiently delimbed. The branches which are removed from the treeduring the delimbing operation fall to the ground adjacent the infeedside of the delimber and thus do not interfere with the operation of thesame.

As mentioned above, the ratio of dimensions of the arm members 40 andlink members 50 is important,

that is, in regard to the pivot centres of the respective 1 onesvThepivot centres of each arm member 40 and ment.

Although not shown, means may be added to the delimber shown which willautomate or semi-automate its operation. For example, the cuttingmembers 30 can be programmed to move to a first selected position rela--tive to frame 20 to a second selected position relative to frame 20 byinstalling for example an electrornechanical'sensing device within thebox-like area of frame 20' and adapting it to operate} in conjunctionwith, for example, any of the crank arm members 74,

' 75 or 76, such sensing device being capable of transpel the samethorugh aperture 14. As the tree is beginning to be propelled by thetree feeding means the cutting blades 32 of the arcuate cutting members30 are brought into contact with the periphery of the trunk of the tree.This is accomplished by activating fluid cylinder 81 by operation ofthe'related hydraulic valving control therefor. This causes retractionof the "piston rod end of the fluid cylinder 81 andconsequently mittingan electronic signal to hydraulic valve mechanisms controlling theoperation of fluid cylinder 81.

FIGS, 8, 9'and 10 as mentioned previously disclose a tree topping device100 which includes an arm member assembly 200 and a power means 300.

' It will be noted that thetree topping device 100 is secured todelimber 10 adjacent the infeed side thereof and is adapted to functionin conjunction with delimber tachably secured by suitable means. A shaft203 is inserted within tube support member 202 and supported therein ona pair of bearings 204 mounted in spaced relation adjacent the terminalends of tube support member 202. Bearings 204 may be press'fitted intotube support member 202 or held captive by other suitable means.Lubrication access is also provided to bearings 204 via lubricationnipples and related passageways not shown. Bearings 204 may be of anysuitable commercially available type.

An arm member sub-assembly 205 comprises an arm member 206 which may befabricated from suitable bar stock, contoured and of sufficient lengthto sweep across the face of aperture 14 as indicated by the curvedphantom line in FIG. 8 adjacent the free end of arm member 206. Armmember 206 is apertured to receive collar 207 to which it is secured bywelding. A circular end disc 208 is secured by welding to the end faceof collar 207. End disc 208 is apertured to receive the threadedterminal end of shaft 203. Referring to FIG. 10, it will be seen thatarm member sub-assembly 205 is held captive on shaft 203 by acastellated nut and cotta pin 209 and 210 respectively. A thrust washer211 on shaft 203 provides a wear surface between tube support member 202and arm member sub-assembly 205. A key 212 is inserted in a keyway inshaft 203 and collar 207 to provide a locking means therebetween andthus avoid slippage. Key 212 is retained endwise by a shoulder in shaft203 and end disc 208.

Referring now to the power means 300 connection to shaft 203. A collarassembly 213 is mounted upon the terminal end of shaft 203 and issecured thereto by a castellated nut and cotta pin 215 and 216respectively, nut 215 being threaded upon shaft 203. Key 214 preventsslippage between collar assembly 213 and shaft 203. Key 214 is heldcaptive in similar fashion to key 212.

Collar assembly 213 includes a collar 217 which may be made in similarfashion to collar 207, and circular end disc 219 welded together. Athrust washer 211 is mounted upon shaft 203 adjacent collar assembly 213and tube support member 202.

A pair of lugs 220 depend from collar assembly 213 being secured to thesame in spaced relation by welding or the like. Lugs 220 may be madefrom plate-like material, contoured and suitably apertured to receivecollar assembly 213 and pin 221.

Power means 300 includes a fluid cylinder 301 hav-- ing the cylinder endsecured to frame 20 shown in phantom via a bracket assembly 302 andhaving the piston rod end connected to lugs 220 via pin-221.

Fluid cylinder 301, like fluid cylinder 81, may be of any suitablecommercial type which includes similar spherical bearings at the pistonrod end and cylinder end as discussed in respect of fluid cylinder 81.Fluid cylinder 301 is connected to a suitable pressurized fluid supplyand its operation controlled via suitable valving not shown.

With regard to fluid cylinder 301 piston rod end connection to lugs 220.Referring to FIG. 10, it will be seen that pin 221 which includes a heatportion 221A and threaded portion 2218 is inserted through apertures inlugs 220 and held captive by locking nut 221C. A pair of spacers 221Dare inserted on either side of the spherical bearings to take up endplay. A block 221E is welded to lug 220 adjacent the head 221A of pin221 to prevent rotation of the same. Lubrication fittings are threadedinto suitable passageways in fluid cylinder 301 adjacent the sphericalbearings as shown in FIG. 8.

Bracket assembly 302 may be fabricated as disclosed in FIGS. 8 and 9which include a plate member 303 welded to frame 20 in the mannerdisclosed and being additionally supported by a pair of gusset members304 which are also welded to frame 20 and member 303. A pair of lugs 305made from plate-like material, contoured and apertured to receive pin221 are welded in spaced relation to member 303 and accommodate thecylinder end portion of fluid cyinder 301. It will thus be realized thatthe cylinder end connection of fluid cylinder 301 to bracket assembly302 is similar to the respective piston rod end connection to lugs 220.

An electro-mechanical switch 400 is mounted upon bracket 401 which is inturn secured to lug 201 by welding or the like.

Electro-mechanical switch 400 may be of any suitable known commercialtype or alternatively of the type shown in FIG. 8 which includeselectrical make and break contacts operated by a plunger with rollersecured thereto and capable of transmitting a signal to operatehydraulic valving controlling the operation of fluid cylinder 301.Switch 400 is secured by a plurality of cap screws 402 to bracket 401.

Bracket 401 may be made as shown from commercially available structuralangle, cut to the general configuration shown and then welded in place.

The tree topping device may be mounted and operated in conjunction withany suitable tree processing unit or units or alternatively be mountedand operated in conjunction with delimber 10.

When the device is mounted to delimber 10 as shown, it may be operatedgenerally as follows:

A tree is processed by delimber 10 in the manner as previously discussedand as the top portion of the tree approaches cutting members 30 namelyat a selected distance between said top portion and the leading face ofsaid cutting members, fluid cylinder 301 is activated by extending thepiston rod end therefrom causing arm member 200 to swing across the faceof aperture 14 and thereby lop off the top of the tree which fallsfreely to the ground or the like. It has been found unnecessary tosharpen the edge of arm member 200, which generally performs the loppingoperation. As arm member 200 rotates with shaft 203 in an anti-clockwisedirection as viewed in FIG. 8, edge 200A eventually makes contact withroller and plunger 2008 on Switch 400 and activates the same sending asignal to control valving controlling the operation of fluid cylinder301. Cylinder 301 is in turn activated to swing arm member 200 in aclockwise direction returning it to a position as shown in FIG. 8.

The tree topping device 100 may be operated semimanually oralternatively, have its operation fully automated.

One example of automated operation is to employ a sensing device such asan electro-mechanical switch of the type mentioned previously, mountingthe same adjacent cutting members 30 or related interconnecting linkagesso that such device is activated by the same when the free ends ofcutting members 30 move to a selected position relative to one anotherand the central axis of aperture 14, said sensing device upon activationtransmitting a signal to operate controls for activating fluid cylinder301 pivoting arm 200. The return of arm 200 to its initial startingposition could, of course, be done by thev means previously discussed.

The importance of the function of tree topping device 100 is to removeunwanted relatively small diameter tree portions and prevent theirentering a tree processing unit. Thus, valuable time is saved inunwanted material.

I claim:

1. A stripper type tree delimber for removing the limbs from a treewhile the same is propelled endwise therethrough comprising:

a. a frame;

b. a plurality of cutting members arranged in circumferential spacedrelation relative to one another around a common axis and each having anarcuate cutting edge;

c. means mounting each of said cutting members on said frame comprisinga link member and an arm member, each pivotally attached to the frameand cutting member providing a parallelogram having the pivot axesthereof parallel to said common axis; and t d. power means secured tosaid arm members and said frame for moving said arm members relative tosaid frame thereby selectively providing movement of said cuttingmembers in a direction toward and away from said common axis.

2. A machine as defined in claim 1 wherein the pivotal connection of theparallelogram is such as to provide relative movement of the cuttingmembers relative to one another in a common plane. f

3. A machine as defined in claim '1 wherein at least four cuttingmembers are mounted on said frame and have a free terminal end movabletoward and away from said common axis at a rate of movement differingprocessing from that of the opposite free terminal end.

4. A machine as defined in claim 1 wherein said cutting members arearranged so as to move relative to one another to form an expandible andcontractible iris-like aperture, the centre axis of such beingsubstantially coincident with said common axis.

5. A machine as defined in claim 3 wherein the terminal ends of saidcutting members are in generally endto-end abutting relationship whenmoved to a position remote from said common axis.

6. A stripper delimber as defined in claim 1 wherein said cuttingmembers are interconnected by further link members synchronizingmovement of the cutting members.

7. A stripper delimber as defined in claim 1 wherein said frame is abox-like assembly having a central aperture through which the trees passendwise during delimbing and wherein said cutting members aresymmetrically arranged aboutthe axis of said aperture.

8. A stripper delimber as defined in claim 7 wherein said power means,and further links interconnecting said cutting members synchronizingmovement of the same are located interiorly of said box-like assembly.9. A stripper type delimber as defined in claim 1 including a furthercutting knife pivotally mounted on said frame for movement about an axissubstantially parallel to said common axis and power means for rotatingsaid further cutting knife about said pivot axis.

1. A stripper type tree delimber for removing the limbs from a treewhile the same is propelled endwise therethrough comprising: a. a frame;b. a plurality of cutting members arranged in circumferential spacedrelation relative to one another around a common axis and each having anarcuate cutting edge; c. means mounting each of said cutting members onsaid frame comprising a link member and an arm member, each pivotallyattached to the frame and cutting member providing a parallelogramhaving the pivot axes thereof parallel to said common axis; and d. powermeans secured to said arm members and said frame for moving said armmembers relative to said frame thereby selectively providing movement ofsaid cutting members in a direction toward and away from said commonaxis.
 2. A machine as defined in claim 1 wherein the pivotal connectionof the parallelogram is such as to provide relative movement of thecutting members relative to one another in a common plane.
 3. A machineas defined in claim 1 wherein at least four cutting members are mountedon said frame and have a free terminal end movable toward and away fromsaid common axis at a rate of movement differing from that of theopposite free terminal end.
 4. A machine as defined in claim 1 whereinsaid cutting members are arranged so as to move relative to one anotherto form an expandible and contractible iris-like aperture, the centreaxis of such being substantially coincident with said common axis.
 5. Amachine as defined in claim 3 wherein the terminal ends of said cuttingmembers are in generally end-to-end abutting relationship when moved toa position remote from said common axis.
 6. A stripper delimber asdefined in claim 1 wherein said cutting members are interconnected byfurther link members synchronizing movement of the cutting members.
 7. Astripper delimber as defined in claim 1 wherein said frame is a box-likeassembly having a central aperture through which the trees pass endwiseduring delimbing and wherein said cutting members are symmetricallyarranged about the axis of said aperture.
 8. A stripper delimber asdefined in claim 7 wherein said power means, and further linksinterconnecting said cutting members synchronizing movement of the sameare located interiorly of said box-like assembly.
 9. A stripper typedelimber as defined in claim 1 including a further cutting knifepivotally mounted on said frame for movement about an axis substantiallyparallel to said common axis and power means for rotating said furthercutting knife about said pivot axis.